Controlling Garden Pests: Aphids

 

Aphids are a very common garden pest. We get them a lot on our sunflowers, and it's usually easy to spot an infestation because there will also be a lot of ants.

Ants are attracted to aphids because of a sticky, sweet substance they produce when feeding, called honeydew. Honeydew isn't the sole food source for ants, but when an aphid colony is in the area, the ants can harvest this nutrient-rich substance continually with less labor than what is required to constantly locate new food sources. Because of this, ants protect aphid colonies, warding off pests and parasites, as well as helping the immobile aphids multiply by spreading them out on infested sunflowers. Here is a good article explaining the relationship between ants and aphids.

Anyway, it's important to get rid of these pests before they get too out of control. A few aphids may not cause noticeable damage, but as populations build, leaves may yellow, twist, discolor or drop off after drying up.

We have found the easiest, most effective way to control the aphid population is by spraying they leaves with a diluted dish soap mixture. We use the blue original Dawn dish soap for this, as it seems to be the safest and is great for lots of different uses around the house.

• Simply fill a spray bottle with water, add a small squirt of the dish soap, and give it a good shake. We don't measure, but I'm guessing it's probably about 1 teaspoon of soap in the 32 oz. spray bottle we use. 

• Spray the affected plant's leaves on both sides with the soapy mixture. Be sure to coat the underside of the leaves with the mixture, as this is where you'll find the highest concentration of aphids.

• Spray the soapy mixture directly onto any aphids you notice falling from the leaves.

• I would suggest rinsing away the soapy residue after one to two hours. Allowing the soap to remain on the leaves for longer than a few hours can cause damage and burning. Use a garden hose or spray bottle filled with plain water to remove the residue. 

Here's a leaf that was sprayed with the soapy mixture and not rinsed after.
The aphids are dead and the ants are gone, but the leaf is not looking too hot.

• Reapply the mixture every few days, or as necessary, to keep the aphid infestation under control.